1. Field of the Invention
The present invention relates to the injection of drill cutting by deposition into the annulus around a well casing and more particularly to the injection of such cuttings in a well being drilled at a much earlier stage than is presently considered feasible.
2. General Background
In oil and gas well development operations, the handling and disposal of the waste material entrained in the fluid during the drilling process, commonly known as the drill cuttings, has become an increasingly difficult problem. Environmental regulations and considerations prohibit or make undesirable the surface disposal of so-called drilling muds and drill cutting. On the other hand certain categories of material produced in the drilling process may be reclaimable as useful construction materials such as various grades of sand or gravel. Such material may be used to back-fill reserve pits and to construct and maintain road beds etc. Moreover, although the disposal of drilling fluids and materials such as clay, shale or fine earth particles, brought to the surface in the drilling process, may be unwanted from an environmental impact perspective, the disposal of these materials into subterranean formations may be acceptable and possibly beneficial.
To this end the present inventive process has been developed with a view towards providing a unique system and method for disposing of certain materials generated during the process of drilling oil and gas wells and the like. The injection of drill cuttings into the annulus of a well bore is not unique. However, the present injection process takes place only during the last phase of the drilling process, generally during the last 20% of the well bore usually after the intermediate casing has been set. Since drill cutting are generated throughout the well drilling process, it is essential that the cutting be contained, stored or otherwise disposed of during the first 80% of the drilling operation, thereby incurring excessive high cost for collection and transportation. Therefore there is a need to utilize the cuttings injection process throughout the drilling process thus reducing cost and adverse environmental impact as a result of transport and disposal of the cuttings at a remote site.